Linezolid

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The summary below is from the full report titled "Linezolid: The First Oxazolidinone Antimicrobial." It is in the 21 January 2003 issue of Annals of Internal Medicine (volume 138, pages 135-142). The author is RC Moellering Jr.

What is the problem and what is known about it so far?

Antibiotics are drugs used to treat bacterial infections. These drugs have been responsible for saving millions of lives over the years. Partially because they are so useful, doctors have tended to overuse them, and this has allowed bacteria to adjust to their presence, becoming resistant to their bacteria-killing effects. As a result of the development of antibiotic resistance, certain types of bacteria have become extremely difficult to treat since few (or no) antibiotics remain effective against them. For this reason, it has become critically important to develop new drugs that can treat these difficult infections.

Why did the author do this review?

To inform the medical community about the development and effectiveness of a new drug, linezolid, which is used to treat several serious antibiotic-resistant infections.

How did the author do this review?

The author reviewed numerous studies conducted on the use of linezolid in treating infectious disease.

What did the author find?

Linezolid is one member of a new class of antibiotics. Linezolid is effective against almost all bacteria of a common type, known as gram-positive organisms, that includes Staphylococcus (staph) and Streptococcus (strep). The term gram-positive refers to a staining process (named after its developer) that is used to distinguish between two types of bacteria. Gram-positive bacteria cause infections acquired in community settings and hospitals.

Linezolid works largely by stopping bacteria from multiplying rather than by killing them. It is also effective in treating certain types of infections due to bacteria known as enterococci that have become resistant to all previously available antibiotics. Linezolid does not damage kidney or liver function. Even though this is a new drug, there is evidence that a few bacteria have already developed resistance, a problem that has been observed most often in seriously ill patients who have dialysis catheters or other prosthetic devices in place. Linezolid can cause high blood pressure when taken in conjunction with common cold remedies that contain phenylpropanolamine or pseudoephedrine. It has also occasionally caused bone marrow suppression (a decrease in the production of new blood cells), although this adverse effect appears to go away once use of the drug is stopped.

What are the implications of this review?

Linezolid is an important addition to the antibiotic options available for treating certain drug-resistant bacteria. Patients with underlying conditions that could lead to bone marrow suppression must be carefully monitored during the course of treatment. This new drug should not be overused, or its effectiveness will also probably be diminished by the emergence of resistant strains of bacteria.